'use strict';
const {
  Model
} = require('sequelize');
module.exports = (sequelize, DataTypes) => {
  class Chapter extends Model {
    /**
     * Helper method for defining associations.
     * This method is not a part of Sequelize lifecycle.
     * The `models/index` file will call this method automatically.
     */
    static associate(models) {
      // define association here
      models.Chapter.belongsTo(models.Course,{as:'course'})
    }
  }
  Chapter.init({
    courseId: {
      type:DataTypes.INTEGER,
      allowNull:false,
      validate:{
        notNull:{msg:'课程ID必须填写'},
        notEmpty:{msg:'课程ID不能为空'},
        async isPresent(value){
          const course = await sequelize.Course.findByPk(value)
          if(!course){
            throw new Error("课程不存在")
          }
        }
      }
    },
    title: {
      type:DataTypes.STRING,
      allowNull:false,
      validate:{
        notNull:{msg:'标题必须填写'},
        notEmpty:{msg:'标题不能为空。'},
        len:{args:[2,45],msg:"标题长度必须是2~45之间。"}
      }
    },
    content: DataTypes.TEXT,
    video: {
      type:DataTypes.STRING,
      validate:{
        isUrl:{msg:"视频地址不正确"}
      }
    },
    rank: {
      type:DataTypes.INTEGER,
      allowNull:false,
      validate:{
        notNull:{msg:'排序必须填写'},
        notEmpty:{msg:"排序不能为空"},
        isInt:{msg:'排序必须为整数'},
        isPositive(value){
          if(value<=0){
            throw new Error("排序必须是正整数。")
          }
        }
      }
    }
  }, {
    sequelize,
    modelName: 'Chapter',
  });
  return Chapter;
};